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Command to request a Self-test
:
In order to authorize the battery contactor self-testing (opening / closing), EMS needs to send a
command using SDO CAN open protocol. This command must be sent:
- Every 6 months or,
- When BMM requires a Self-test (object 2018: Byte6
– Bit0 of TPD03 set to 1).
When the BMM requires a Self-test via CAN, EMS has to request a Self-test in the following 24
hours. If not, BMM will set IMD and IMR values to 0 on CAN open bus (no charge or discharge
authorized).
Then, if EMS always
doesn’t request a Self-test, 10 minutes after battery will open the contactor
and go in
SAFE
mode with alarm 12 (“IBIT undone for 6 months”). The only way to restart the
battery is to switch OFF and ON the battery power supply.
Before requesting a Self-test, EMS must open the battery converter. After self-test
completion, BMU will go in
STANDBY
mode and wait for contactor closing authorization.
To request a Self-test, Bit0 of object 2054h must be set to 1: the contactor self-test is starting on
rising edge of this bit. After the test, d
on’t forget to put this bit to 0 before a contactor closing
request.
For details, see document [RD1].
Time stamp object
:
In order to time stamp data inside the black box, “Time stamp” object (1012h) need to be sent at
least one time at each BMM start-up.
4.15. SOH and EOL definitions
SOH is the battery State Of Health in %.
EOL is the battery End Of Life.
For a new battery, SOH is equal to 100%.
The SOH is equal to 0% when the battery has reached its EOL criteria.
The end of life criteria is based on a capacity loss: it is set at 20% loss of initial capacity.
This value is given by CAN bus in the dedicated object 2036h as indication.
It is not taken in account in SOC and IMD/IMR calculations.
4.16. SOC definitions
“SOC” (CAN open object 2026h) is the battery state of charge calculated according to:
- Cells voltages
- Coulomb-metry
- Battery temperature
The value is smoothened to prevent from sudden jumps that may be caused by:
- A change of the temperature range
- Recalibration on open cell voltage a low current rate
- Cell voltage accuracy
The old SOC CAN open object 2025h (SOC_without_SOH) given in TPDO4 sub-index 5 is
forced to 0 and no longer usable.
5. COMMISSIONING AFTER LONG STORAGE
During storage, the battery cells have a natural self-discharged that is heterogeneous. The
balancing is ensured automatically by SMU boards, but only at a module level (not battery
level).